1. Field of the Invention
This invention relates to an improved ladder attachment apparatus which facilitates the lifting of objects and machinery from the ground and other surfaces to the roof of a building or other elevated position, and more specifically relates to a stabilized, mobile, winch system and assembly which can be used in combination and conjunction with a number of commercially available ladders to provide a stronger, more stabilized ability to position a ladder for more convenient lifting of objects ranging in weight from refrigerant compressors up to considerably heavier objects for the purpose of transporting them to the roof of a building or other surface.
2. Background Information
Various types of ladder hoists, ladder hoist attachments, and ladder and ladder attachments facilitating the lifting of an operator or an object have been known or marketed for use by painting, maintenance and construction personnel. Following are typical inventions which were located during the process of a patent search.
U.S. Pat. No. 3,902,700 to Cox which discloses a portable bridge-crane structure designed to provide means of lifting construction materials and equipment such as compressors for air conditioners to the roof of a building where construction or installation is to be performed.
U.S. Pat. No. 4,128,228 to Ziegelmann discloses an extension ladder hoist having a hoist for raising and lowering articles from one elevation to another in which one portion of the support is a ladder.
U.S. Pat. No. 4,598,795 to Larson discloses a ladder hoist attachment consisting of a boom and prop combination that allows a conventional ladder to be used to hoist heavy loads.
U.S. Pat. No. 4,770,273 to McMakin et al discloses a ladder lift apparatus usable to lift heavy loads from the ground to a roof surface including a horizontally positioned, shoulder mounted lifting bar or beam with a winch means, fastened to the bar or beam where one end of the lifting bar or beam is pivotally connected to a vertically positioned ladder or extension ladder, with means to allow pivotal rotation of the upper end of the ladder toward the roof to deposit the load on the roof or into a window of a multi-story building.
U.S. Pat. No. 5,139,108 to Pate discloses a stabilized ladder power winch assembly which includes a winch mounting subassembly with two channeled portions, a reversible mount bracket subassembly with a cantilevered portion, a tiltable prop subassembly having a safety rung support extension, a frame and corresponding and aligned handle and leg portions, and a stabilizer subassembly with lateral support portions.
None of the prior art devices available are light weight for easy handling, nor simple to carry in a truck without occupying any extra space, nor are they quick to assemble and disassemble, nor easy to use and having the capability of more than one special purpose and yet packaged all in one unit and capable of lifting objects of both a lighter and heavier weight with little or no strain, therefore minimizing personal injury and maximizing safety.
One such unit that uses a shoulder apparatus to hold the boom in place while lifting the object. This can cause an unbalance in the system while trying to turn the winch by hand and at the same time trying to balance the weight as it is being lifted. As the object gets closer to the top of the ladder, the system becomes top heavy. Because of the lack of base stabilizing, this becomes a dangerous situation if the mechanic shifts a slight amount of weight to one side of the body, causing a side tipping action to begin and very difficult to control once it is started. Once the object has reached the top and is ready to be set on the roof, the serviceman must carefully walk backwards pivoting the base of the ladder as it approaches the building and then setting the object on the roof.
This same system uses a tri-pod set up for heavier objects. This improves the lift to the top of the ladder but the difficulty still exists when the object is ready to be set onto the roof. Someone now has to lift the tri-pod which now has more weight due to the larger object causing more top heaviness and having to be more careful not to start the tipping action from side to side while bringing the ladder towards the building to set the object down. Again setting up for a dangerous situation.
There are still other units that use a boom as a handle and a lifting mechanism with a motorized winch which attaches to the ladder but again this limits the unit to light lifting and also the inconvenience of locating power to the electric hoist. If this same hoist were converted to manual hoisting, it would create difficulty in holding and lifting at the same time.
There are still other units that use U-shaped wrap around ladder brackets with feet that lean against the wall of the building and then manually lifting the object to the roof from the ground. This unit again limits the weight and the size of the object to be lifted, because of the wrap around bracket which limits the size of the object by the size of the bracket. The swivel system, which it uses to set the object on the roof is interfered with by the roof bracket which the unit uses to stabilize the ladder. This would have to be removed before lowering the object onto the roof or the object and the swivel could not spin around.
The instant invention overcomes the above safety and weight limits because of its unique design. Due to its versatility, it allows for more than just roof-type work.